Just Add Monsters was acquired by Argonaut Games in October 2000 with Jez San OBE joining the board. They released their first game, Kung Fu Chaos in 2003, as a 1st-party Xbox exclusive.

In 2004, Argonaut got into financial trouble. The Just Add Monsters division was saved after a management buy-out, and reformed as Ninja Theory Ltd. Their future was consolidated by signing the title Heavenly Sword (2007) at SCEE as a PS3-exclusive. The studio's third title, Enslaved: Odyssey to the West was their first multiplatform release. It continued in the third-person action genre and was released in 2010.

The studio worked on a reboot of the Japanese Devil May Cry franchise, DmC: Devil May Cry, which was released in 2013. They also contributed to the development of 2015's Disney Infinity 3.0.